Adding some widget addition flow tests

> Added two dummy widget providers: with config and without config
> Added tests for verify widget config flow

Change-Id: I4577f085abe8f8b82047b644c71cc9065358153a
diff --git a/src/com/android/launcher3/ItemInfo.java b/src/com/android/launcher3/ItemInfo.java
index 82c7ab8..aec6c7d 100644
--- a/src/com/android/launcher3/ItemInfo.java
+++ b/src/com/android/launcher3/ItemInfo.java
@@ -166,7 +166,7 @@
     /**
      * Write the fields of this item to the DB
      */
-    void onAddToDatabase(ContentWriter writer) {
+    public void onAddToDatabase(ContentWriter writer) {
         if (screenId == Workspace.EXTRA_EMPTY_SCREEN_ID) {
             // We should never persist an item on the extra empty screen.
             throw new RuntimeException("Screen id should not be EXTRA_EMPTY_SCREEN_ID");